All Given

Please read what Chiller said above.

Wait for next rewarding zones

for which you need points?

nice

I am just loving it. But I can't find out how to challenge others

challenging others is when you get high score in a game and when you open the same game later,you will find a line in yellow color at the bottom of the game. there you can click and challenge all your friends who are in your friends list. this was followed when there was options like submit games. but now they have stopped that. so may be you may not get now. but those who played before they might get that option even now for which all games they have got high score before. but for new people to get now there is no way to it.